Circadian Rhythm

Our body "clocks" are set to the sun.  We are not nocturnal animals, rather, we thrive during the day.  Our peak hormonal production time is around 8am.  If we get an adequate amount of rest and sleep at night, these hormones will be at peak production, during the peak times and will stay at that peak longer.  The less rest we get, the least likely we are to peak and stay there for a great duration of time.  In the evening, when the sun starts to go down, we get drowsy because of a hormone that is released into our bloodstream called melatonin.  Melatonin makes us drowsy and tired.
Listen to your body at this time, and go to sleep!  If we get to bed before 11pm, our adrenal hormones (epinephrine and nor-epinephrine) can recharge fully.  They recharge between the hours of 11pm and 1am.  We use adrenaline all day everyday in some capacity or another.  Just walking and talking requires both of these hormones, not just physical, strenuous exercise and stressors!  Get to bed before 11pm!
If we get an adequate amount of rest, and we get exposure to sunlight before 9am, we will set our bodies up to naturally produce more performance and life-enhancing hormones, most notably growth hormone, which then works to increase every other hormone in the body as well. 
Set your Circadian Rhythm the right way, and reap the benefits of living a healthier, more energetic lifestyle and perform better in all aspects of life!